The disclosure of Japanese Patent Application No. HEI 11-78229 filed on Mar. 23, 1999 including the specification, drawings and abstract is incorporated herein by reference in its entirety.
1. Field of the Invention
The present invention relates to an airbag control apparatus and, more particularly, to an airbag control apparatus having a manual cutoff switch that can be manually operated to bring an airbag apparatus installed in a vehicle into an ineffective state.
2. Description of the Related Art
Japanese Patent No. 2753968 (U.S. Pat. No. 5,612,876) and Japanese Patent Application Laid-Open No. HEI 8-216825 disclose technologies for bringing a passenger seat-side airbag apparatus into an ineffective (activation-prevented) state when a child or a child seat occupies a passenger seat of a motor vehicle.
An airbag control apparatus of JP No. 2753968 is capable of changing an airbag apparatus between a normally effective (standby) state and an ineffective state by detecting the weight of a vehicle occupant on a seat cushion through the use of a seat load sensor provided in the seat cushion. In an airbag control apparatus of Japanese Patent Application Laid-Open No. HEI 8-216825, a manual cutoff switch is provided in an airbag ignition circuit. By manually operating the manual cutoff switch, an airbag apparatus can be changed between a normally effective state and an ineffective state.
However, in the airbag control apparatus of JP No. 2753968, there exist areas in which the detection by the seat load sensor provided in the seat cushion is difficult, that is, generally termed gray zones. Therefore, there is a possibility that even though an adult actually is present on the seat cushion, it will be determined that an adult is not seated on the seat cushion, and therefore the airbag apparatus will be switched to the ineffective state, depending on the sitting posture of the adult occupant. In the airbag control apparatus of Japanese Patent Application Laid-Open No. HEI 8-216825, the manual cutoff switch can be operated at will by an occupant. Therefore, there is a possibility of a false or inadvertent operation of the manual cutoff switch, that is, there is a possibility that the airbag apparatus will be in the ineffective state in a case where the apparatus actually needs to be in the normally effective state, or that the airbag apparatus will be in the normally effective state in a case where the apparatus actually needs to be in the ineffective state.
Accordingly, it is an object of the invention to provide an airbag control apparatus capable of preventing inadvertent operation of a manual cutoff switch and therefore preventing inadvertent activation of an airbag apparatus.
In accordance with the invention, an airbag control apparatus includes a manual cutoff switch for changing an airbag apparatus between an effective state and an ineffective state in accordance with a will of an occupant, an occupant-detecting sensor that detects presence or absence of a seated occupant or a body build of the seated occupant, and a control device for changing the airbag apparatus between the effective state and the ineffective state by controlling the manual cutoff switch in accordance with a detection signal from the occupant-detecting sensor.
This airbag control apparatus is able to change the airbag apparatus between the effective state and the ineffective state by the control device controlling the manual cutoff switch in accordance with the detection signal from the occupant-detecting sensor. Therefore, the airbag control apparatus is able to prevent inadvertent activation of the airbag apparatus due to inadvertent or false operation of the manual cutoff switch.
In the airbag control apparatus of the invention, the control device may allow the manual cutoff switch to be switched to an ineffective side only when a state with no occupant or with an occupant having a body build less than a predetermined body build is detected by the occupant-detecting sensor.
Therefore, since the manual cutoff switch is allowed to be switched to the ineffective side only when the state with no occupant or with an occupant having a body build less than the predetermined body build is detected by the occupant-detecting sensor, it becomes impossible to switch the manual cutoff switch to the ineffective side in a condition where the airbag apparatus needs to be effective. Hence, the airbag apparatus can be reliably activated when the activation of the airbag apparatus is actually needed.
The airbag control apparatus of the invention may further include a lock mechanism that prevents the manual cutoff switch from being switched to an effective side when a state with no occupant or with an occupant having a body build less than a predetermined body build is detected by the occupant-detecting sensor.
Therefore, since the lock mechanism prevents the manual cutoff switch from being switched to the effective side when the state with no occupant or with an occupant having a body build less than the predetermined body build is detected by the occupant-detecting sensor, it becomes impossible to switch the manual cutoff switch to the effective side in a condition where it is desirable that the airbag apparatus be ineffective. Hence, the inadvertent activation of the airbag apparatus due to inadvertent operation of the manual cutoff switch can be prevented.
The airbag control apparatus of the invention may further include a lock mechanism that prevents the manual cutoff switch from being switched to the ineffective side when an occupant having a body build equal to or greater than the predetermined body build is detected by the occupant-detecting sensor.
Therefore, since the lock mechanism prevents the manual cutoff switch from being switched to the ineffective side when an occupant having a body build equal to or greater than the predetermined body build is detected by the occupant-detecting sensor, it becomes impossible to switch the manual cutoff switch to the ineffective side in a condition where the airbag apparatus needs to be effective. Hence, the inadvertent activation of the airbag apparatus due to inadvertent operation of the manual cutoff switch can be prevented.
The airbag control apparatus of the invention may further include a forcibly switching mechanism that forcibly switches the manual cutoff switch from the ineffective side to an effective side when an occupant having a body build equal to or greater than the predetermined body build is detected by the occupant-detecting sensor.
In this construction, when an occupant having a body build equal to or greater than the predetermined body build is detected by the occupant-detecting sensor, the forcibly switching mechanism forcibly switches the manual cutoff switch from the ineffective side to the effective side. Therefore, if the manual cutoff switch should be at the ineffective side in a condition where the airbag apparatus needs to be effective, the forcibly switching mechanism will forcibly switch the manual cutoff switch from the ineffective side to the effective side, so that the air-fuel ratio can be properly activated.
The airbag control apparatus of the invention may further include a forcibly switching mechanism that forcibly switches the manual cutoff switch from an effective side to the ineffective side when a state with no occupant or with an occupant having a body build less than the predetermined body build is detected by the occupant-detecting sensor.
In this construction, when the state with no occupant or with an occupant having a body build less than the predetermined body build is detected by the occupant-detecting sensor, the forcibly switching mechanism forcibly switches the manual cutoff switch from the effective side to the ineffective side. Hence, if the manual cutoff switch should be at the effective side in a condition where it is desirable that the airbag apparatus be ineffective, the manual cutoff switch will be forcibly switched from the effective side to the ineffective side.
In the airbag control apparatus of the invention, the occupant-detecting sensor may be a seat load sensor that is provided in a seat cushion and that is capable of detecting weights in three ranges.
Therefore, it becomes possible to discriminate a state with no occupant, a state with an occupant having a body build less than the predetermined body build, and a state with an occupant equal to or greater than the predetermined body build. Hence, in accordance with a signal discriminating the three states from one another, whether to deploy an airbag body or not can be selected. Furthermore, in accordance with such a signal, the manner of deploying the airbag body can be controlled.
Furthermore, in the airbag control apparatus of the invention, the manual cutoff switch may be operated by using an ignition key, and may include a key cylinder that has an ON position where the airbag apparatus is normally effective, and an OFF position where the airbag apparatus is normally ineffective.
Therefore, since the manual cutoff switch is constructed so as to be operated by using an ignition key, the manual cutoff switch can be operated substantially only before the engine is started, and inadvertent operation of the manual cutoff switch in other occasions, for example, during driving, is prevented.
Still further, in the airbag control apparatus of the invention, the manual cutoff switch may be operated by using an ignition key, and may include a key cylinder that has an ON position where the airbag apparatus is normally effective, an OFF position where the airbag apparatus is normally ineffective, and an AUTO position where the airbag apparatus is controlled based on the detection signal from the occupant-detecting sensor.
Therefore, since the manual cutoff switch is constructed so as to be operated by using an ignition key, the manual cutoff switch can be operated substantially only before the engine is started, and inadvertent operation of the manual cutoff switch in other occasions, for example, during driving, is prevented. Besides, since the manual cutoff switch has three positions, the freedom in selection is increased.
The airbag control apparatus of the invention may further include an information-indicating device for, when the manual cutoff switch is at the AUTO position, indicating whether the airbag apparatus is in the effective state or the ineffective state.
With regard to the occupant-detecting sensor, there normally exist broad gray zones where the precision of detection by the occupant-detecting sensor is not sufficient. Therefore, there is a possibility that even though an occupant having a body build equal to or greater than the predetermined body build is seated, the airbag apparatus may be made ineffective depending on the sitting posture of the occupant, the motion of the occupant""s hands, or the like. However, in the above-described construction, when the manual cutoff switch is at the AUTO position, the information-indicating device is activated to indicate whether the airbag apparatus is in the effective state or the ineffective state. Therefore, through the information-indicating device, an occupant can check whether the detection by the occupant-detecting sensor is correct or incorrect. That is, it becomes possible to advise an occupant to switch the manual cutoff switch to a proper position if necessary.